Distributed Multi-User Multiple-Input Multiple-Output (MU-MIMO) is an attractive technology for achieve more parallelism of transmissions and fewer collisions. Almost inevitably, distributed Uplink MU-MIMO (UL-MU-MIMO) for, uncoordinated systems, such as Wi-Fi®, requires that raw samples be fronthauled to a centralized baseband processor. Distributed Downlink MU-MIMO (DL-MU-MIMO) can work in the same way.
Lighting-as-a-Service (LaaS) offers dense ceiling cabling that is useful for distributed MU-MIMO. Due to cost pressures, 1 Gigabit Ethernet (1 GigE), as opposed to Multigigabit (MGig) and 10G, is likely to dominate the options for cabling for LaaS in other similar systems.
Despite compression, with control signals etc., approximately 20 bits per in-phase (I) and quadrature (Q) sample is a reasonable estimate for data to be transmitted and/or received. Thus, a 1 GigE cable can carry 2*20 MHz (800 Mbps) of traffic with some margin. However, this is not enough bandwidth for modern Wi-Fi systems that can operate as high as 4*80 MHz. Similarly, 4*160 MHz Wi-Fi traffic cannot be supported by 10 GigE.
A way is needed to synthesize larger bandwidths of data over cables that have relatively low capacity.